The present invention relates to a wire tensioning apparatus for pulling wires arranged inside a structure to reinforce the structure.
In general, an elevated structure that is built to span a river, a strait, a canal, a traffic route, or a structure to provide passage over it is referred to as a bridge.
Such a bridge consists of an upper structure that allows for passage, and a lower structure that supports the upper structure. In case of the upper structure, there occurs a deflection phenomenon caused by a repetitive fatigue load and a repeated load or a self-weight load during or after the installation of the upper structure. As a result, a problem is caused in that the upper structure is unfortunately collapsed by its deflection phenomenon.
Thus, in an attempt to reinforce the upper structure, a plurality of wire bundles each of which is a bundle of approximately 10 to 14 wires is arranged inside the upper structure and is tensioned tightly, thereby preventing the upper structure from being deflected downward.
A wire tensioning apparatus is used to reinforce the structure. In this case, the wire tensioning apparatus is joined to one ends of wires to pull the wires. The wire tensioning apparatus includes a body, a plurality of rods that is at least partially joined to the inside of the body, and a clamp block coupled to the rods and configured to clamp the wires.
Fluid is introduced into the body of the wire tensioning apparatus and rods pull the wires while being displaced by the pressure of the fluid to cause the wires to be maintained in a tightly tensioned state. However, it is required that a large quantity of fluid should be supplied to the inside of the body while the plurality of rods is displaced axially simultaneously. A high-pressure fluid is needed to allow the plurality of rods to be moved simultaneously. For this reason, many loads are generated in the body, resulting in occurrence of a problem of damage of the body and the rods.
In the meantime, if the number of wires constituting the wire bundles is smaller than that of the rods, only some of the rods are connected to the wires via the clamp block. In this case, while the plurality of rods is displaced axially simultaneously, rods that are not connected to the wires are also displaced axially. Consequently, power loss occurs unnecessarily.